1. Field of the Invention
The present invention relates to an electron beam drawing apparatus which draws a circuit pattern of a semiconductor integrated circuit on a wafer, a deflection amplifier, a deflection control device, an electron beam drawing method, a method of manufacturing a semiconductor device, and an electron beam drawing program.
2. Description of the Background Art
In a semiconductor manufacturing field, since an electron beam drawing apparatus has a pattern producing function, the device is applied to photomask preparation or direct drawing for small amounts of large varieties, and more particularly to trial manufacturing of a state-of-the-art device. In the electron beam drawing apparatus, an electron source image by a point beam system or a beam forming opening image by a variable forming system is projected or scanned on a sample surface to form a fine pattern. Especially in the latter variable forming system, a beam shape is controlled by a rectangular forming opening and a forming deflection unit, and a reduced image is projected on the sample surface to form the pattern efficiently. Therefore, in the variable forming system, speeding-up of the drawing is realized as compared with the point beam system in which the electron source image is transferred.
However, the conventional electron beam drawing apparatus has a problem that a drawing position deviates from a designed position depending on a property of a deflection amplifier. This is because an element temperature in the deflection amplifier, and especially a standard resistance for determining an output voltage change with an operation situation of the deflection amplifier. Accordingly, the drawing position deviation occurs depending on a density difference of the device pattern, and deterioration of a drawing precision is caused.
Moreover, a temperature change occurs in a stage depending on the operation situation. That is, in a case where the stage continuously runs, the temperature of the stage itself changes with a friction heat or a heat conducted from a motor which drives the stage. As a result, the stage expands or contracts. A stage position of the electron beam drawing apparatus is generally measured by a laser interferometer. However, for example, when the stage expands, and accordingly a position of a mirror attached to the stage changes, the stage position cannot be exactly measured. The temperature change of the stage causes a temperature change of a wafer. Especially, since an Si wafer has a thermal expansion ratio larger than that of any other general material for use in the stage, the wafer comparatively easily expands or contracts. As a result, there occurs a problem that a desired drawing position cannot be irradiated with any beam. Since the stage of the electron beam drawing apparatus is in vacuum, the heat conducted to the stage does not easily escape, and this influence is serious as compared with another exposure device whose stage is in atmospheric air.
It is to be noted that this type of electron beam drawing apparatus is disclosed in Jpn. Pat. Appln. KOKAI Publication Nos. 6-13299, 6-36997, and 2003-188075.
Moreover, this type of exposure technology is disclosed in Jpn. Pat. Appln. KOKAI Publication Nos. 2000-124113, 2001-267238, 2002-246295, and 2003-151885.